1. Technical Field
The present invention relates to reciprocating machinery and more particularly to piston and connecting rod components of the types used in reciprocating engines, fluid pumps, compressors, vacuum pumps and other types of piston-driven machinery.
2. Background Art
Power transmission hardware such as pistons, connecting rods and crankshafts are known in the art for use in reciprocating engines. In such engines, one or more pistons are generally disposed in a hollow engine cylinder. A pressure source is applied within the closed volume of the cylinder to displace the piston axially along the cylinder. The linear motion of the piston can be converted to rotating shaft power using a connecting rod coupled to the piston at one end and coupled to an eccentric crankshaft at the opposite end. Typically, the crankshaft includes a rod bearing offset from the crankshaft axis of rotation, and the connecting rod is pivotally attached to the crankshaft at the offset location. As the piston moves toward the crankshaft, linear motion of the piston is converted to rotational motion of the crankshaft as the connecting rod forces the crankshaft to rotate about the connecting rod axis of rotation. Conversely, as the crankshaft rotates, additional connecting rods connected at various offset angles relative to the crankshaft axis of rotation can convert rotational motion of the connecting rod into linear motion of additional pistons for providing a compression stroke in one or more additional cylinders of the engine.
During both power and compression strokes, conventional piston and connecting rod assemblies are subjected to mechanical stress due to the pressure and heat associated with moving the piston inside the cylinder. To better manage this stress and to prevent accelerated piston and connecting rod wear and failure, conventional piston and connecting rod assemblies typically include solid metal materials. Such materials can increase the weight of the engine components resulting in reduced efficiency and lowered engine performance.
It is generally desirable in the art of reciprocating engines to produce connecting rod and piston assemblies having a reduced weight. By reducing the weight of the engine components greater fuel efficiency and improved engine performance can be realized. Additionally reduced weight and reduced material volume in the piston and connecting rod assembly can improve heat transfer and power output in many applications.
Others in the art have attempted to reduce connecting rod and piston assembly weight and material volume by reducing the thickness of the connecting rod and also by reducing the thickness of the piston skirt and/or piston face. However, a reduction in the thickness and material volume of these parts can reduce structural integrity resulting in premature wear or engine failure.
Further improvements to conventional piston and connecting rod assemblies for reducing the weight and material volume of engine components and for improving engine performance are needed.